Not sure if this will help but here's a example 10.10 from the book 'Programming in C' by steven G. Kochan.
Code:
// a dictionary to look up words and return an definition.
//preprocessor statements
#include<stdio.h>
//define structure
struct entry
{
char word[10];
char definition[50];
};
//test to see if strings are equal
int compare_strings(char s1[], char s2[])
{
int i =0, answer;
while (s1[i] == s2[i] &&
s1[i] != '\0' && s2[i] != '\0')
++i;
if ( s1[i] < s2[i] )
answer = -1; // s1 < s2
else if ( s1[i] == s2[i] )
answer = 0; //strings are equal
else
answer = 1; //s1 > s2
return (answer);
}
//function to look up words in a dictionary
int lookup(struct entry dictionary[], char search[],
int entries)
{
int mid, result;
int high = entries - 1;
int low = 0;
int compare_strings(char s1[], char s2[]);
while ( low <= high )
{
mid = (low + high) / 2;
result = compare_strings(dictionary[mid].word, search);
if (result == -1)
low = mid + 1;
else if (result == 1)
high = mid - 1;
else
return mid;
}
return -1;
}
main()
{
struct entry dictionary[100] =
{
{"aardvark","a burrowing african animal" },
{"abyss", "a bottomless pit" },
{"acumen", "mentally sharp, keen" },
{"addle", "to become confused" },
{"aerie", "a high nest" },
{"affix", "to append; attach" },
{"agar", "a jelly made from seaweed" },
{"ahoy", "a nautical call of greeting" },
{"aigrette","an ornamental cluster of feathers" },
{"ajar", "a US Marine's haircut" },
};
char word[10];
int entries = 10;
int entry_number;
int lookup(struct entry dictionary[], char search[],
int entries);
printf("Enter word: ");
scanf("%9s", word);
entry_number = lookup (dictionary, word, entries);
if (entry_number != -1)
printf("\n%s\n\n\n", dictionary[entry_number].definition);
else
printf("Sorry, that words is not in my dictionary\n\n");
}
